another TBF project
#1
Timing Belt failure project
here's my latest project, 1993 GTS 5 speed. this car has been my dream car since high school, too bad it needs tons of work. hope you don't mind i share it with you guys. any comments or suggestions are appreciated. engine pull this weekend, i'll follow up then. TIMING BELT FAILURE
Last edited by Shark_Week; 09-28-2010 at 11:59 PM. Reason: update
#3
I dont see a broken belt, must mean thrust bearing failure.
Looks like a sharp car. I would recommend the clear lenses from Nicole at www.hookedoncars.com
Looks like a sharp car. I would recommend the clear lenses from Nicole at www.hookedoncars.com
#5
the belt didn't break. there were two or three areas with quite a few missing belt ribs. the longest section is in the last picture. about 6 to 8 inches stripped clean. i'm thinking too much slack in belt as the cause? all pulleys seemed to turn easily. the tension on the belt seemed loose but i don't know what to compare it to. it's my first 928.
#6
#7
Great score on the project - a 5-speed GTS that requires you to take the heads off, yum! While its apart, make sure the pistons have the oil drain holes drilled through.
Whats the interior/mileage etc. like? No rub strips, and original wheels is nice.
Whats the interior/mileage etc. like? No rub strips, and original wheels is nice.
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#9
the interior is mint, only dusty from lack of detail by previous owner and driver's seat is worn at the side bolster. getting in and out i suppose. only 90k on odometer. i'll check the wheel size but to me they look fat. would of had the engine out today but; the two bolts on top of bellhousing are giving me fits, do i disconnect a/c or just hang it, removed four bolts at the motor mounts(the ones facing down) is that all of them, remove clutch assembly? sorry to ask, i havn't received my manuals yet and i couldn't wait !
#11
Nice car I hope you get it back to running status.
If you do as Wally suggested pull the plugs and turn it over by hand after you install the belt.
From the looks of all the teeth missing I would say you have some bent valves
If you do as Wally suggested pull the plugs and turn it over by hand after you install the belt.
From the looks of all the teeth missing I would say you have some bent valves
#13
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Hang the AC pump from a piece of wire. The top bolts on the bellhousing are a job. I've used a very long bunch of 1/2" extensions and a breaker bar. Others have used a box wrench with a pipe over it from the top. Motor mounts have 19MM pointing down just above the steering rack, or a 19MM on top of the mount, neither are easy to get to, bottom has to come out. The four 17MM bolts that hold the rack on have heads on top that are also a mess to get to. Best to jam something in the flange of the cover and the head then zip the 17MM off, then 13MM come off easy, and the rack drops down. Pinch bolt on clutch intermediate shaft at lower rear bellhousing should be loosened. It may allow the PP to come out easier.
Welcome, and put your location in your sig, or near your avatar.
<edit; I'm assuming you didn't test for bent valves before pulling? It was prolly the original belt.>
Welcome, and put your location in your sig, or near your avatar.
<edit; I'm assuming you didn't test for bent valves before pulling? It was prolly the original belt.>
#15
Rods: Somebody is going to suggest you change the rods, since the '93 GTS rods were designed poorly by Porsche. If you decide to change the rods, there are some choices. The powder forged rods in the '87 and some engines are really strong, basically the 951 strong but with narrower big end width. There are lighter and stronger 4340 steel H-beams available from Pure Performance Motorsports for a reasonable price as well, I am about to experiment with those.
Oiling: There are a number of oiling changes that people will likely suggest, too. One is that the piston oil holes should be drilled thru, this was already brough up. There are various scraper systems and windage trays available, on top of the GTS baffle. An oil pan spacer is helpful for a number of reasons. John Kuhn has a new block chimney box, which combiend with Pro-Vent will solve the intake oil problems. Hoses and breathers.
Camshafts: The GTS exhaust cam is junk. Someone is going to suggest you replace that. There are a number of cam options available, Elgin/Morton S3+, S3 stock, Carl's weld/reground, 944 webcam profiles, Lizards's new billet cams etc.
Headwork: If you start "improving" or rebuilding the heads, a black hole that sucks all your money will open. If a professional sees the heads, he's going to prescribe new valve guides immediately. Then, he's going to see the valve stem grooves, which will be beat up. And the valves have worn out because fo the bad guides, so new valves. New valves? Might as well get bigger intake valves, like the 968 valves, but hey then you need new seats too. Then you need new lifters, since the lighter ones are available, and once you have those you might as well get better springs so the valvetrain will not be banged up. The spring options include shimming the stock springs, 944, 968, Ford Pinto, Mod Ford beehives, etc. And let's shave off some for higher compression compression.
Fuel: Now, you are making more power, so you need possibly a Bosch 044 pump and maybe bigger injectors. Definitely a fuel rpessure regulator for tweaking. And then shark tuning ont he dyno.
Exhaust: Why go thru all this with stock exhaust? X-pipe in, then bettwr mufflers, hell stainless steel new everything. Oh, and cats from Random Tech.
In other words, the mother of all escalations! Cut your credit cards before this happens to you!
Oiling: There are a number of oiling changes that people will likely suggest, too. One is that the piston oil holes should be drilled thru, this was already brough up. There are various scraper systems and windage trays available, on top of the GTS baffle. An oil pan spacer is helpful for a number of reasons. John Kuhn has a new block chimney box, which combiend with Pro-Vent will solve the intake oil problems. Hoses and breathers.
Camshafts: The GTS exhaust cam is junk. Someone is going to suggest you replace that. There are a number of cam options available, Elgin/Morton S3+, S3 stock, Carl's weld/reground, 944 webcam profiles, Lizards's new billet cams etc.
Headwork: If you start "improving" or rebuilding the heads, a black hole that sucks all your money will open. If a professional sees the heads, he's going to prescribe new valve guides immediately. Then, he's going to see the valve stem grooves, which will be beat up. And the valves have worn out because fo the bad guides, so new valves. New valves? Might as well get bigger intake valves, like the 968 valves, but hey then you need new seats too. Then you need new lifters, since the lighter ones are available, and once you have those you might as well get better springs so the valvetrain will not be banged up. The spring options include shimming the stock springs, 944, 968, Ford Pinto, Mod Ford beehives, etc. And let's shave off some for higher compression compression.
Fuel: Now, you are making more power, so you need possibly a Bosch 044 pump and maybe bigger injectors. Definitely a fuel rpessure regulator for tweaking. And then shark tuning ont he dyno.
Exhaust: Why go thru all this with stock exhaust? X-pipe in, then bettwr mufflers, hell stainless steel new everything. Oh, and cats from Random Tech.
In other words, the mother of all escalations! Cut your credit cards before this happens to you!